This invention relates to a solenoid actuator utilized in a musical instrument having a keyboard.
Such solenoid actuators are used as actuators of an automatic performance piano, for example. Examples of such application are disclosed in U.S. Pat. Nos. 3,426,304 and 4,031,796.
The solenoid actuator disclosed in these patents is in the form of a well known electromagnetic plunger comprising an electromagnetic coil, a movable core or plunger slidably received in the electromagnetic coil, and a magnetic yoke for forming a flux path. A plurality of solenoid actuators are driven by electrical signals formed by reproducing prestored signals so as to operate the keys of the keyboard as if they were depressed by hands.
Generally, a conventional piano is designed to have an ample space to accommodate the actuators for the automatic performance at accurate positions but not designed to compactly incorporate the solenoid actuators in the space. Accordingly, to incorporate the solenoid actuators for effecting automatic performance, the construction becomes complicate and expensive and the size becomes large.